Installation of sand drains

ABSTRACT

Formation of sand drains in the earth by drilling and forcing a fluid at high velocity to wash out a hole and thereafter filling the hole by forcing filler material down through a pipe; the pipe being outfitted with special valve control means to control the flow of fluid and filler therethrough in generally inverse manner.

United States Patent 1 Godley et al.

[ 51 Jan. 2, 1973 [22] Filed:

[54] INSTALLATION OF SAND .DRAINS [75] Inventors: Augustus P. Godley,Hohokus; Francis M. Fuller, Washington Township, Bergen County; CharlesR. llouk, Scotch Plains; Henry A. Nelson Holland, Ridgewood; George J.Gendron, Oradell, all of NJ.

[73] Assignee: Raymond International Inc., New

York, N.Y.

Feb. 6, 1968 [21] Appl. No.: 703,440

[52] US. Cl. ..6l/ll, 61/5364, 6l/53.74, 61/63 [51] Int. Cl .Q ..E02b11/00, E02b 5/34 [58] Field of Search ...61/1 1, 10, 63, 53.52, 53.62,61/53.6, 53.64, 53.66, 53.74; 175/21 [5 6] References Cited UNITEDSTATES PATENTS Landau ..61/63 3,358,458 12/1967 Phares ..6l/l0 3,420,0631/1969 Bodine, Jr

3,426,538 2/1969 Turzillo 3,608,317 9/1971 Landau 624,714 5/1899Washington... 1,173,355 2/1916 Jones ..6l/53.74

FOREIGN PATENTS OR APPLICATIONS 619,171 12/1926 France ..6l/53.62

265,150 10/1913 Germany 105,426 6/1924 Switzerland ..61 /53.62 33/65791958 Japan 7 Primary Examiner-Jacob Shapiro Attorney-Ward, McElhannon,Brooks & Fitzpatrick [57] ABSTRACT Formation of sand drains in the earthbydrilling and forcing a fluid at high velocity to wash out a hole andthereafter filling the hole by forcing filler material down through apipe; the pipe being outfitted with special valve control means tocontrol the flow of fluid and filler therethrough in generally inversemanner.

12 Claims, 19 Drawing Figures INSTALLATION OF SAND DRAINS This inventionrelates to the installation of sand drains and, more particularly, itconcerns improvements by which both the effectiveness and economy ofsand drain installation are improved.

Sand drains are regions of high water permeability placed artificiallyin the earth and connected to a region of minimum fluid pressure such asthe atmosphere. Essentially, sand drains function to permit relativelyrapid water pressure release from locations in the earth where excesswater pressures have developed due to construction operations. Excesswater pressures in the ground can be built up as a result of theplacement of heavy structures or earth fills on the ground, or thedriving of pilings into the ground. Because of high excess waterpressures the stability of such structures in earth fills may be poor.Furthermore, such structures and earth fills will incur settlements withtime as the excess water pressure is gradually dissipated at a ratedepending upon the water permeability of the natural soil. By providingregions of high moisture permeability close to these water pressureconcentrations it is possible to obtain dissipation of the waterpressure effects within a very short time so that a stable condition maybe achieved before further construction is undertaken.

Generally, sand drains are constructed by forming a vertical hole in theearth and filling the hole with sand or other moisture permeablematerial. Actually, it is the hole itself, which is open to the groundsurface, that achieves the moisture equalization effects. The sand orother moisture permeable substance however is needed to maintain and tostructurally reinforce the vertical hole while at the same time allowingrelatively free flow of water to the surface.

Experience has shown that the effectiveness of a sand drain is verydependent upon the manner in which it is built including both theformation of the hole and in the placement of the sand or othermaterial. The generally known hole forming methods utilizing scraping orpounding techniques tend to disrupt the natural earth formation in thevicinity of the peripheral surface of the hole being formed in such amanner that a loss of moisture permeability takes place. Also, if thesand or filler material is not properly placed, areas of overcompactnessor underfull may result along the drain hole. Each of these conditionswill result in a loss of moisture permeability. In the case ofovercompactness, the porosity of the fill becomes decreased; and in thecase of underfull, arching may result with voids in the drain hole whichwill allow cave-ins.

The present invention overcomes the abovedescribed difficulties andpermits the installation of effective and reliable sand drains with aminimum of expense and effort.

According to one aspect of the present invention a sand drain isconstructed by forming a hole in the earth, flushing the interior of thehole with a fluid to wash out spoil therefrom and to condition itsinternal surfaces, and then forcing fill material down through a conduitto fill the hole up from the bottom thereof so that the fill materialwill displace the washing fluid out through the top of the hole.

As hereinafter described in detail, the present invention may be carriedout by a simultaneous drilling and washing action whereby a fluid iscontinually forced down through a conduit into the bottom of the hole atsufficient velocity to carry spoil up with it to the surface of thehole. Sand or fill material may thereafter be carried down the sameconduit by fluid moving at a slower rate so that in moving up inside theformed hole it proceeds at a slow enough velocity to allow the fillmaterial to remain at the bottom.

According to a further aspect of the present invention, there isprovided novel sand drain formation equipment comprising elements whichserve to form and flush out the sand drain hole and also to deposit thefill material therein. This equipment includes an elongated pipe havingdrilling means at its lower end and means for supplying both water orother fluid and sand or fill into its upper end. Valve means areprovided to control the rate of fluid and till down through the pipe ingenerally inverse velocity relationship and means are provided to lowerand raise the pipe during the drilling and filling phases respectively.

According to a still further aspect of the present invention a sanddrain hole is filled with water which is stirred to effect suspension ofthe drilled earth in the water. Drilling and stirring may beaccomplished simultaneously by rotating water jets and a stirring paddletogether in the hole. Thereafter, the water and earth suspension isflushed out of the hole. This is achieved by forcing a largedisplacement element down into the hole, while leaving a small annularclearance about its outer surface to permit the water to rise up aroundit. The large displacement element may take the form of a hollow tubehaving an openable bottom sealed to it .with a frangible seal. The tubeis filled with sand or other sand drain solids, and then air is admittedto the interior of the tube under pressure. This blows open the bottomand allows the sand to flow out into the interior of the hole.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other'structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent constructions as do not depart from the spiritand scope of the invention.

Specific embodiments of the invention have been chosen for purposes ofillustration and description, and is shown in the accompanying drawingsforming a part of the specification, wherein:

FIG. 1 is a side elevational view illustrating a system for forming sanddrains according to the present invention;

FIG. 2 is an enlarged fragmentary view, partially in section,illustrating an upper portion of the system of FIG. 1;

FIG. 3 is a perspective view illustrating a valve interconnectionlinkage system utilized in the system of FIG. 1; v

FIGS. 4 and 5 are views illustrating sand drains forming system of FIG.1 during intermediate and final stages of a sand drain formingoperation;

FIG. 6 is a side elevational view of a sand drain forming system forminga second embodiment of the present invention;

FIGS. 7 and 8 are views illustrating the sand drain forming system ofFIG. 6 during intermediate and final stages of a sand drain formingoperation;

FIG. 9 is an enlarged fragmentary view, partially in section of theupper portion of the system of FIG. 6;

FIG. 10 is a perspective view illustrating a control valve arrangementused in the system of FIG. 6;

FIG. 11 is an enlarged fragmentary view of the lower portion of thesystem illustrated in FIG. 6;

FIG. 12 is a sectional view taken along lines l212 of FIG. 11;

FIG. 13 is a fragmentary view similar to FIG. 9, but showing amodification thereof;

FIG. 14 is a side elevational view of a sand drain drilling arrangementaccording to a further modification;

FIG. 15 is an enlarged front elevational view of the bottom portion ofthe drilling arrangement of FIG. 14;

FIG. 16 is a side elevational view of the bottom portion shown in FIG.15;

FIG. 17 is a side elevational view of a portion of a sand drain flushingarrangement according to a further modification;

FIG. 18 is a perspective view of the lower end of the flushingarrangement of FIG. 17; and

FIG. 19 is a side elevational view of the upper portion of the flushingarrangement of FIG. 17.

As illustrated in FIG. 1, a sand drain forming system, illustratedgenerally at 10, is set up on a ground surface 12 into which a sanddrain is to be formed. The system 10 includes an elongated vertical pipe14, at the lower end of which are provided mechanical cutting bits 16. Arotary drive mechanism 18 is coupled to the upper end of the pipe 14 tocause it to rotate in the direction of an arrow A. Means, not shown, areprovided to lower the rotating pipe 14 downwardly into the earth. As thepipe 14 rotates the cutting bits 16 break away chunks of earth therebyforming a vertical hole 20. The broken away chunks of earth are removedin a manner to be described.

Immediately above the drive mechanism 18, there is provided a valvehousing 22 having a lower outlet 24 which communicates through the drivemechanism 18 to the interior of the pipe 14. The housing 22 additionallyis formed with an upper sand inlet region 26 and a lateral fluid inletregion 28.

As shown in FIGS. 1 and 2 there is provided a flapper valve member 30which is pivotally mounted within the housing 22 in such a manner thatit alternately closes off and opens the upper sand inlet region 26 andthe lateral fluid inlet region 28.

The flapper valve member 30 is mounted on the housing 22 by means of anaxle 32. A crank arm 34 is also connected to the axle 32 exteriorly ofthe housing 22 for actuating the flapper valve 30.

A sand hopper 36 is mounted immediately above the sand inlet 28 andserves to guide sand down via the inlet 26 and the housing 22 into thepipe 14 when the flapper valve 30 is in its lowermost position asillustrated in FIG. 2. A flushing nozzle 38 is mounted centrally withinthe hopper 36 and points downwardly towards the sand inlet region 26 ofthe housing 22. The flushing nozzle 38 is secured to the side of thehopper 36 by means of a conduit 40 which in turn is connected via afluid control valve 42 to the fluid inlet region 28 of the housing 22.The fluid inlet region 28 in turn is connected by means of a fluidconduit 44 to a pump 46. The inlet of the pump 46 is connected via aninlet conduit 48 to a T-connection 49 from which it receives freshmakeup water from an external source (not shown) and recycled water froma sump 50 located closely adjacent the hole 20. A fluid pressure gage 52is mounted at the output side of the pump 46 to provide an indication ofthe amount of fluid flow being utilized by the system.

As shown in FIG. 2 the fluid supplied by the pump 46 passes up throughthe fluid conduit 44 and into the fluid inlet region 28 of the housing24. A portion of this fluid also passes through the flushing controlvalve 42, the flushing fluid supply line 40 and down through theflushing nozzle 38 located in the hopper 36. The flow of fluid throughthe flushing nozzle is controlled by means of the flushing fluid controlvalve 42. As shown in FIG. 2 this valve comprises a housing 54 withinwhich a cylindrical valve element 56 rotates. The valve element 56 hasan internal passage 58 therethrough which, when aligned with theflushing fluid conduit 40 and the fluid inlet region 28, as shown inFIG. 2, pennits the passage of flushing fluid to the nozzle 38. On theother hand, when the valve element 56 is rotated so that its internalpassage 58 goes out of alignment with the inlet region 28 and theflushing fluid conduit 40, the flow of fluid through the flushing nozzle38 is stopped.

Turning now to FIG. 3, it will be noted that the flapper valve element30 and the flushing fluid control valve 56 are interconnected by meansof a linkage mechanism which includes a pair of link arms 60 and 62 eachconnected at one end to one of the shafts 32 and 64 on which the valveelements are mounted. An interconnecting link 66 pivotally interconnectsthe other end of each of the two link arms 60 and 62. The mechanismcomprising the links 62 and 66 serves to coordinate the movement of thevalve members 30 and 56 in such manner that when the flapper valvemember 30 is in its upper position closing off the upper sand inlet 56(as shown in FIG. 1) the flushing fluid valve element 56 is in aposition such that it also closes off the flow of fluid through theflushing conduit 40 to the flushing nozzle 38. Conversely, when theflapper valve element 30 is in its downward position as shown in FIG. 2closing off the fluid inlet region 28, the flushing fluid valve member56 is moved to a position permitting the flow of fluid through theflushing conduit 40 to the flushing nozzle 38. This fluid then flowsdownwardly together with the sand in the hopper 36 down through thehousing 22 and the pipe 14.

Operation of the above-described system to fonn a sand drain isillustrated sequentially in FIGS. 1, 4 and 5. As shown in FIG. 1, thehole 20 is first formed in the earth by operation of the drive mechanism18 which rotates the pipe 14 so that mechanical bits 16 dig into theearth as the entire assembly is lowered. During this time, the flappervalve 30 is in its upper position as shown in FIG. 1, thereby preventingthe flow of sand or fluid down through the hopper 36 and into the pipe14. However during this time, the flapper valve 30, as shown in FIG. 2,opens the fluid inlet region 28 so that the pump 46 may supply fluidcontinuously and in large quantities down through the interior of thepipe 14. As illustrated in FIG. 1, the rapid flow of fluid down throughthe pipe 14 causes the cut away particles of earth or spoil to be washedupwardly toward the top of the hole so that a continuous washing actionis effected along the walls of the hole 20.

The liquid and spoil slurry which is washed up out of the hole 20 flowsalong the surface 12 back into the sump 50 where the solid particles arepermitted to settle. The liquid itself however, may be reused in thewashing and flushing operation. Accordingly it is pumped back via theT-element 49 to the inlet side of the pump 46. As indicated previously,additional makeup water may be supplied via the other arm of theT-element 49.

When the hole 20 has been formed to a desired depth and the systemreaches the position shown in FIG. 4, the drive mechanism 18 is stoppedand the valve arrangement is actuated so that the flapper valve member30 moves to its lowermost position as shown. In this position, theflapper valve member 30-closes off the flow of fluid through the lateralinlet region 28. At the same time it opens the upper inlet region 26 tothe hopper 36. When this takes place, a sand skip 70 is lifted to aposition above the hopper 36 by suitable means (not shown) and is causedto dump a load of sand 72 into the hopper 36.

During the dumping of sand down into the hopper 36 the flushing fluidcontrol valve 42 is in a position such that fluid from the pump 46 flowsthrough the flushing conduit 40 and down through the flushing nozzle towash the sand from the hopper down through the pipe 14 so that it isdeposited in the bottom of the hole 20.

It will be noted that the diameter of the flushing conduit 40 isconsiderably restricted with respect to the diameter of the fluid supplyconduit 44. Thus the flow rate of fluid through the pipe 14 from theflushing nozzle 38 during the depositing operation is considerably lessthan the flow rate which takes place via the fluid inlet region 28during the digging operation. As a result of this lessened flow rate,the fluid velocity at the bottom of the hole 20 is insufficient to washthe deposited sand back up to the surface 12 of the earth. Accordingly,the sand is carried down through the interior of the pipe 14 and is leftto remain in the hole 20. It has been found that the use of continuouslyflowing fluid, both to achieve a flushing action during the diggingoperation and to carry sand to the bottom of the hole during thedepositing operation, results in the provision of a sand drain which isespecially effective in permitting the free drainage of liquid from thesurrounding earth. There is no undue compaction of the earth in thevicinity of the sand drain, and the surfaces of the sand drain, i.e.,the earth-sand interface is smooth; and freeflow transition is providedfor the liquid in this region.

The'arrangement shown in FIGS. 6-12 utilizes a high velocity water jetarrangement for the digging operation. As shown in FIG. 6, there isprovided a sand drain forming system, illustrated generally at 80, whichincludes an elongated pipe 81 and a housing 82 fitted to the top of thepipe. The housing 82 includes an upper sand inlet region 84 and alateral fluid inlet region 86. A sand hopper 88 is mounted on top of theupper sand inlet region 84 to direct sand into the housing when theregion 84 is opened. Fluid supply means (not shown) are provided tosupply fluid via an inlet pipe 90 to the lateral fluid inlet region 86.

lnsidethe housing 82 there is provided a plug type valve member 92 whichmoves in a vertical direction between an upper position, as shown inFIG. 6 and a lower position as shown in FIG. 7. In its upper position,the valve member 92 fully closes the upper sand inlet region 84 andfully opens the fluid inlet region 86. In its lower position the valvemember 92 fully opens the upper sand inlet region 84 and partiallycloses the fluid inlet region 86.

As can be seen in FIGS. 9 and 10, the plug type valve member 92 isconnected at its upper end through a pivotal link 94 to one end of acrankarm 96. The other end of the crankarm 96 is mounted on a crankshaft98 which in turn extends through, and is supported horizontally forrotation by, the walls of the sand hopper 88. The outer end of thecrankshaft 98 is provided with a pulley or sprocket 100 about which abelt or chain 102 is looped. This belt chain is pulled by manual orautomatic means (not shown) to rotate the crankshaft 98 and change thevertical position of the valve member 92.

As shown in FIG. 6, the lower end of the valve member 92 is connectedvia a rod 104, inside the pipe 81 to a jet fonning nozzle controlelement 106. This element is moved up and down with the valve member 92;and in its upper position, as shown in FIG. 6, the nozzle controlelement cooperates with the lower edge of the pipe 81 to form highvelocity jet nozzles. In its lower position, as shown in FIG. 7 thenozzle control element 106 allows sand and water to flow freely and atrelatively low velocity out from the bottom of the pipe 81.

The construction of the jet forming nozzle control element 106 is bestshown in FIGS. 11 and 12. It will be seen that this element includes anouter conically shaped tip portion 108 and an inner conically shapedplug portion 110. A plurality of longitudinally extending channels 11 1are formed along the outer surfaces of both portions of the element; andwhen the element is in its upper or restricted position as shown in FIG.11,

these channels cooperate with the lower edge of thepipe 81 to define lowcross section, high velocity jet nozzles. These nozzles serve to controlthe flow of water out from the bottom of the pipe 81 so that it proceedsin the form of sharply defined streams 112 of high velocity. Thesestreams are directed at the surrounding earth at the bottom of the holebeing dug; and they simultaneously break up and wash away the earth inthis region. The flow rate of the water in the streams 112 is maintainedat a valve sufficient to carry the washed away earth up to the top ofthe hole 20.

When the jet forming nozzle control element is moved to its lowerposition, its inner conically shaped plug portion 110 moves away fromthe lower edge of the pipe 81 to define a greatly enlarged outlet crosssection through which water and sand may pass at a relatively high flowrate but at a much reduced linear velocity.

In operation, the system of FIGS. 6-12 undergoes the same overallsequence as described in connection with the system of FIGS. 1-5. Thusthere is provided a simultaneous digging and washing operation, followedby a fluid conveyor type depositing operation. During the diggingoperation, the valve member 92 and the nozzle control element 106 are intheir uppermost positions as shown in FIG. 6. Thus no sand is permittedto flow down through the hopper 88 during this time. On the other handthe lateral fluid inlet region 86 is fully opened and a large fluid flowproceeds down through the pipe 81. This fluid flow is converted by therestricted nozzle control element 106 into high velocity jet streams 112which dig out and wash away particles of earth from the bottom of thehole 20.

When the hole 20 is formed to the desired depth, the belt or chain 102is pulled to turn the pulley or sprocket 100 thereby rotating thecrankshaft 98 and causing the crankarm 96 to move the pivotal link 94 sothat the valve member 92 and the jet forming nozzle control element 106are moved to their lowermost positions as shown in FIG. 7. At this timesand is dumped into the hopper 88 from a skip 114. With the valve member92 and the nozzle control element 106 in their lowermost positions, sandflows freely downwardly from the hopper 88 through the valve housing 82and the pipe 81 and out past the nozzle control element 106. Thisdownward flow of sand is aided by the reduced but still substantial flowof water which the valve member 92 permits to flow in via the lateralfluid inlet region 86 in the housing 82. This fluid flow, whilesufficient to convey sand down to the bottom of the hole 20, isinsufficient to carry it back up to the top of the hole. Thus, the sandis evenly and smoothly deposited in the hole and eventually fills it asshown in FIG. 8. Of course, the sand drain forming system 80 which wasgradually lowered during the digging operation, is raised during thedepositing operation.

FIG. 13, shows a modification to the system of FIGS. 6-12 wherein thereis provided a fluid control valve 116 connected to the lateral fluidinlet region 86 of the valve housing 82, and a flushing conduit 118leading from the valve 116 through the wall of the hopper 88 to aflushing nozzle 120 which is aimed down into the bottom of the hopper.This arrangement serves to provide an additional flushing during thedepositing operation to assist in moving sand down from the hopper 88and into the pipe 81.

FIGS. 14-19 illustrate a still further modification of the presentinvention. As shown in FIG. 14 there is provided an elongated hollowrotary drill pipe 120 which is rotated continuously by means of a rotarydrive mechanism 122. A water tight swivel joint 124 is providedimmediately above the rotary drive mechanism and is connected via aninlet hose 126 to a supply of pressurized water (not shown). The watersupplied via the hose 126 passes through the swivel joint 124 and downthrough the rotating drill pipe 120. The entire assembly is supported bymeans of a hook 128 which can be controlled to lower and raise theassembly into and out ofa hole 129 being cut into the earth.

At the lower end of the drill pipe 120 there is provided a stirringpaddle 130 and a pair of cutting jets 132. As shown in FIGS. and 16, thestirring paddle 130 simply comprises a flat plate fitted up into alongitudinal slot 134 in the bottom of the rotary drill pipe 120. Thepaddle divides the lower interior of the pipe 120 into two separatechannels 136 and 138; and these channels lead out to individual waterjet openings 140 and 142 located on opposite faces of the paddle 130.

As the rotating drill pipe 120 is lowered into the hole 129, pressurizedwater is forced out of the jet openings 140 and 142 and cuts into theearth. The size of the hole thus cut depends upon the size of the jetopenings, the water pressure used, and the rotational and longitudinalspeed of the assembly. These variables are chosen however such that thehole which is cut is of a larger diameter than the distance-across thepaddle 130. This ensures that the paddle will not wipe" the sides of thehole and thus impair its efficiency as a sand drain. The purpose of thepaddle is to keep the loosened material being dug in a stirred upcondition and thereby maintained in a suspended state in the water sothat it may thereafter be washed out of the hole along with the water.

From time to time soil conditions will be encountered which will notallow penetration by the water jets. In such case the paddle 130 may beprovided with a plurality of outwardly protruding teeth 144 which,during rotation, will tend to scratch or scarify the sides of the hole.This action will weaken the earth and permit the water jets to do sandactual cutting, thereby avoiding the wiping action which results fromthe use of blade type bits.

After the hole in the earth has been formed to the desired depth, therotary drill pipe 120 and its associated cutting elements are withdrawn.Thereafter, as illustrated in FIG. 17, a sand drain tube 146 is loweredrapidly into the hole 129. The sand drain tube 146, as shown in FIG. 18is a hollow steel pipe having an outer diameter slightly less than thediameter of the hole 129. Around the lower edge of the tube 146 thereare welded a plurality of downwardly projecting pointed bars 148. Anexpendable bottom plate 150, of wood or similar material is hammeredonto the bottom of the tube 146 and is held in place by the pointed bars148. A cross bar 152 is welded diametrically across the lower end of thetube 146 to provide reinforcement for the bottom plate 150. A sealingcompound 154, e.g., roofing slate or the equivalent, is applied to sealthe bottom plate to the tube.

Reverting to FIG. 17, it will be seen that as the tube 146 with itsbottom plate is forced rapidly down into the hole 129, it produces alarge displacement of the water and earth suspension in the hole andcauses it to rush rapidly upwardly up and out from the hole. This highvelocity upward movement of water causes it to carry with it, thecuttings previously made by the water jets and previously put intosuspension by the stirring action of the paddle 130. The rapid upwardmovement of water along the sides of the hole 129 also produces awashing action which serves to clean the surfaces of the hole. Thisimproves the porosity in the vicinity of the hole and enhances itsability to transmit water from the surrounding earth.

When the tube 146 is fully inserted into the hole 129, it is filled withsand as indicated in FIG. 19. As there shown, sand is poured from a sandskip 156 and into the tube 146 through a sand opening 158 formed nearits upper end. The sand opening 158 is provided with an airtight door160 mounted on a pivot 162. The opening and closing of the door may becontrolled by means of a line 164 attached to an arm 168 extending outfrom the door on the opposite side of the pivot 162. serves as When thedoor 160 is closed the interior of the tube 146 is pneumatically sealed.Thereafter, air which is pressurized to about 100 pounds per square inchis admitted to the interior of the tube 146 via an air connection 170also located near the top of the tube. Because of the porosity of thesand filling in the tube this air pressure is communicated throughoutthe tube and is applied to the bottom plate 150. The air pressure issufficient to blow the bottom plate off as indicated in FIG. 19. As aresult, the sand within the tube flows out into the hole 129. The actionof the pressurized air atthis point serves to lubricate the individualsand particles, permitting the tube 146 to be removed while at the sametime properly placing the sand in the drilled hole. As the tube 146 iswithdrawn from the hole the air pressure is reduced so a s to preventblowing of the top of the thus completed sand drain.

In cases where it is believed that the tube 146 might tend to rubagainst one side or the other of the hole 129 either when it is beingpushed down into the hole or while it is being withdrawn, the tube maybe provided with a series of longitudinal ribs 172 as shown in FIG. 18.These ribs will center the casing in the drilled hole while reducing thewiped (and possibly smeared) area to a minimum.

A massive weight 174 as shown in FIG. l9'may be provided at the upperend of the tub 146 to assist in forcing it down into the hole 129against the opposition of the water being forced out of the hole.

Having thus described the invention with particular reference to thepreferred forms thereof, it will be obvious to those skilled in the artto which the invention pertains, after understanding the invention, thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of the invention, as defined by the claimsappended thereto.

What is claimed is:

l. A method of forming a sand drain in the earth which comprises thesteps of drilling a hole in the earth, introducing a fluid into saidhole to substantially fill said hole, causing said fluid to flow overand wash spoil out through the top of said hole, and thereafter forcingdrain solids down through a pipe in the hole to fill same forced downinto said hole by making a slurry thereof with fluid and washing samedown through a pipe, the fluid velocity being maintained below thatwhich will carry said solids up to the top of said hole.

2. A method as in claim 1 wherein said fluid is forced into said holeduring said drilling to provide simultaneous drilling and washing.

3. A method as in claim 1 wherein said fluid is forced into the bottomof said hole in the form of high velocity jet sprays to effect saiddrilling.

4. A method as in claim 1 wherein said during said overflow at least aportion of said fluid is recovered and d f h h n fr ne t o a i ri ciafm4 wherein said fluid is caused to pass out of the top of said hole intoa settling sump where washed out spoil may settle and wherein saidportion of said fluid is thereafter pumped back into said hole.

6. A method as in claim 1 wherein said fluid is forced into said holefrom the bottom thereof.

7. A method of forming a sand drain in the earth which comprises thesteps of drilling a hole in the earth, filling said hole with water,stirring the water in the hole to suspend the drillings, rapidly forcinga large displacement element having a cross section smaller than thehole down into it, thereby to produce rapid upward movement of waterfrom the hole to carry with it the suspended drillings, and thereafterfilling the hole with sand drain solids.

8. A method as in claim 7 wherein said large displacement element isforced down the center of the hole to direct the upward flow of wateralong the hole surfaces, thereby to achieve a washing action along saidsurfaces.

9. A method as in claim 7 wherein said large displacement element is ahollow elongated tube and wherein sand drain solids are admitted to saidhole via said tube.

10. A method as in claim 9 wherein said tube is provided with anopenable bottom element sealed thereto with a frangible seal and whereinfollowing admission of sand drain solids to said tube and insertion ofsaid tube into said hole pressurized air is admitted to said tube toblow open said bottom and release said sand drain solids.

11. A method as in claim 7 wherein said drilling and stirring areachieved simultaneously by the rotation of earth cutting water jets.

12. A method as in claim 11 wherein a paddle eleup from the bottomthereof, thereby to displace said mantis rotated with rotation ofsaidjetsfluid out through the top of said hold, said solids being can"Patent No. 3 707 UNITED STATES PATENT OFFICE Dated January 1973Inventor(s) GODLEY et al Column 1, lines 45 Column 8, line 4,

line 11,

line 28,

line 45,

Column 9, line 4 line 22,

line 2s,

line ma line 46,

lines 46' line 51 -water jets l32--;

for ropfing--;

' sufficient;

to read -hole--;

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below: I

and 49, "underfull" to-read underfill-;

for "individual water jet: openings 140 and 142" to read the openings ofthe water jets l32-;

for "jet openings 140 and 142" to read delete the word- "sand";

for "e.g., roofing" read --e.g.- of the type used for "means of a line164" to read means of a line 1166-;

for "so s' to read -so as-; l for "1 72" to read -l74--; I

fin: "174" to a 176%;

"we" read that,

for "fluid" u read -liquid-;

and 47, for "to substantially fill said hole causing said fluid" to readat'a first rate for "fluid'l-to read --+liquid-,-, for "hold" fQRMP051059 o-gas USCOMM-DC maze-Pea 1' us. sqvgnnnzm' Pniiqrmc Glyphs: waso-ass-su UNITED STATE S PATENT OFFICE CERTIFICATE 0 F CORR E C'lI ONPatent No. 3 r 7 I 4 Dated January 2 1973 GODLEY et a1. 7 Inventor(s) Itis certified that error appears in the above-identified patents and thatsaid Letters Patent are hereby corrected as shown below:

Page 2 continued V n Column 10, line 2, for "fluid and" to readE-said liquid-;

, lines- 2 and 3, for the fluid velocity being maintained" to read wh.,ile the liquid is 'flowed at a second, lesser, rate-; lines 5, 8 and 12,for "fluid" to read li quid-;

line-llyfor "said during said to read --during-*-";

lines l4, l7 and 19 for "fluid" to read -liquid;

Signed and sealed this 27th day of November 1973 (SEAL) Attesti. a

EDWARD M.FLETCHER,JR.' I 'RENE D. TEGTMEYER I Attesting Officer ActingCommissioner of Patents

1. A method of forming a sand drain in the earth which comprises thesteps of drilling a hole in the earth, introducing a fluid into saidhole to substantially fill said hole, causing said fluid to flow overand wash spoil out through the top of said hole, and thereafter forcingdrain solids down through a pipe in the hole to fill same up from thebottom thereof, thereby to displace said fluid out through the top ofsaid hold, said solids being forced down into said hole by making aslurry thereof with fluid and washing same down through a pipe, thefluid velocity being maintained below that which will carry said solidsup to the top of said hole.
 2. A method as in claim 1 wherein said fluidis forced into said hole during said drilling to provide simultaneousdrilling and washing.
 3. A method as in claim 1 wherein said fluid isforced into the bottom of said hole in the form of high velocity jetsprays to effect said drilling.
 4. A method as in claim 1 wherein saidduring said overflow at least a portion of said fluid is recovered andused for further washing.
 5. A method as in claim 4 wherein said fluidis caused to pass out of the top of said hole into a settling sump wherewashed out spoil may settle and wherein said portion of said fluid isthereafter pumped back into said hole.
 6. A method as in claim 1 whereinsaid fluid is forced into said hole from the bottom thereof.
 7. A methodof forming a sand drain in the earth which comprises the steps ofdrilling a hole in the earth, filling said hole with water, stirring thewater in the hole to suspend the drillings, rapidly forcing a largedisplacement element having a cross section smaller than the hole downinto it, thereby to produce rapid upward movement of water from the holeto carry with it the suspended drillings, and thereafter filling thehole with sand drain solids.
 8. A method as in claim 7 wherein saidlarge displacement element is forced down the center of the hole todirect the upward flow of water along the hole surfaces, thereby toachieve a washing action along said surfaces.
 9. A method as in claim 7wherein said large displacement element is a hollow elongated tube andwherein sand drain solids are admitted to said hole via said tube.
 10. Amethod as in claim 9 wherein said tube is provided with an openablebottom element sealed thereto with a frangible seal and whereinfollowing admission of sand drain solids to said tube and insertion ofsaid tube into said hole pressurized air is admitted to said tube toblow open said bottom and release said sand drain solids.
 11. A methodas in claim 7 wherein said drilling and stirring are achievedsimultaneously by the rotation of earth cutting water jets.
 12. A methodas in claim 11 wherein a paddle element is rotated with rotation of saidjets.